Air quality in Gwangju

Does Gwangju have air pollution?

Gwangju is a city in South Korea, finding itself in the center of the Jeolla region, an agricultural area that is famous for its variety of cuisine. It is also the 6^th largest city in the country, with some 1.49 million people living there, and as such would have a number of pollution related issues due to day to day human activities such as commuting, as well as the tourist industry contributing to these factors.

In regards to its pollution levels taken over 2019, Gwangju was recorded with a PM2.5 reading of 28.7 μg/m³, placing it into the higher end of the ‘moderate’ pollution bracket. To be classed as moderate, a reading of anywhere between 12.1 to 35.4 μg/m³ needs to be registered, and as the name implies, despite not having the overwhelmingly bad levels of pollution that other countries in Asia may have, it still stands to reason that the air pollution levels in Gwangju may cause some issues for its residents, particularly those who belong to vulnerable demographics. These would include young children, the elderly, along with those that have preexisting medical conditions or compromised immune systems. Pregnant mothers would also be particularly at risk, due to the vast amounts of complications that arise when an unborn baby is exposed to pollution.

This 2019 reading of 28.7 μg/m³ placed Gwangju into 476^th place out of all cities ranked worldwide, as well as 22^nd place in all cities ranked in Korea, coming in just behind Buan and Hwaseong. As mentioned, whilst lacking the overtly bad levels of pollution, Gwangju still has elevated levels of air contamination, with certain months coming in with very poor readings of PM2.5, and as such has some way to go if it is to reduce its air pollution levels and get closer to the World Health Organizations target goal of 10 μg/m³ or less, for the cleanest and therefore safest quality of air.

What are the main causes of pollution in Gwangju?

There are several main causes of pollution in Gwangju, some with similar sources and others that find a different origin. One of these different sources may be trans-border smoke blowing over from China, with China’s massive economy and growing industrial sector putting out vast quantities of pollution, that when subject to the appropriate weather conditions, can be blown over to Korea where it can affect the local levels of pollution, particularly in a city such as Gwangju that finds itself on the western side of Korea and therefore in closer proximity.

However, despite outside influences, much of Koreas pollution is generated internally, with their own massive economic growth coupled with a population boom also driving up localized forms of pollution. Major ones would be emissions from vehicles, as well as smoke and fumes coming from factories, power plants and other similar industrial areas. Many of these sites run on fossil fuels such as coal, or diesel for heavy machinery, and as such would put out large amounts of related pollutants into the atmosphere, driving up the year round ambient readings of PM2.5.

When is the air most polluted in Gwangju?

Observing the data taken over 2019, it is apparent that the months with the worst levels of pollution come at the very beginning of the year, showing PM2.5 readings that far surpass the rest of the year, and skewing the yearly average by a considerable amount.

It appears that the decline in air quality actually begins in the months towards the end of the previous year, and thus reach a peak in the first three months of the following year. Readings taken in October, November and December all show a consistent and somewhat steep rise in pollution levels.

October came in with a reading of 15.7 μg/m³, followed by November at 23.6 μg/m³, and then December at 35.2 μg/m³. The highest months as mentioned were of course January through to March, with readings of 50.7 μg/m³, 45.1 μg/m³ and 51.6 μg/m³ respectively, putting them in the upper echelons of the ‘unhealthy for sensitive groups bracket’ and displaying that March was indeed the most polluted month out of the year in 2019.

When is the air at its cleanest in Gwangju?

In contrast to the times when the air was observed to be at its worst, the months that came in with the cleanest (albeit still with slightly elevated levels of pollution) readings of PM2.5 were April through to October. After the extremely polluted first three months of the year, with March coming in at 51.6 μg/m³, pollution levels dropped suddenly down to 22 μg/m³ in April, and despite a small jump back up in May, continued to drop for the rest of the year, with June through till September showing a consistent decline in levels of smoke, haze and other pollutants in the air.

June through to September came in with readings of 18.7 μg/m³, 17.1 μg/m³, 15 μg/m³ and then 11.5 μg/m³ in September, making it not only the cleanest month of the year but also the only month to drop down a ranking into the ‘good’ level of air pollution bracket, one that requires a very fine margin of 10 to 12 μg/m³ to achieve classification.

What are the main pollutants found in the air in Gwangju?

With much of its pollution stemming from internal sources such as vehicular emissions, there would be accompanying pollutants such as nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) permeating the atmosphere, with nitrogen dioxide being of particular prominence due to its high release from vehicles, often showing up in high ground level and satellite readings over areas that see high volumes of traffic passing through them.

Other pollutants of note are black carbon and volatile organic compounds (VOC's), both of which are released from the incomplete combustion of fossil fuels, as well as the burning of organic matter that can take place in rural or lower income districts to provide heat during the colder months as well as energy for cooking.

Black carbon is a very harmful particulate matter that has effects on both the health of people as well as on the environment. Some examples of the aforementioned VOC's include chemicals such as benzene, toluene, xylene and formaldehyde, yet again very harmful and very easy respire due to their volatile nature that causes them to become gases at lower temperatures.